basename.c

/* basename.c -- return the last element in a file name Copyright (C) 1990, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */#include <config.h>#include "dirname.h"#include <string.h>#include "xalloc.h"#include "xstrndup.h"/* Return the address of the last file name component of NAME. If NAME has no relative file name components because it is a file system root, return the empty string. */char *
last_component (charconst *name)
{
charconst *base = name + FILE_SYSTEM_PREFIX_LEN (name);
charconst *p;
bool saw_slash = false;
while (ISSLASH (*base))
base++;
for (p = base; *p; p++)
{
if (ISSLASH (*p))
saw_slash = true;
elseif (saw_slash)
{
base = p;
saw_slash = false;
}
}
return (char *) base;
}
/* In general, we can't use the builtin `basename' function if available, since it has different meanings in different environments. In some environments the builtin `basename' modifies its argument. Return the last file name component of NAME, allocated with xmalloc. On systems with drive letters, a leading "./" distinguishes relative names that would otherwise look like a drive letter. Unlike POSIX basename(), NAME cannot be NULL, base_name("") returns "", and the first trailing slash is not stripped. If lstat (NAME) would succeed, then { chdir (dir_name (NAME)); lstat (base_name (NAME)); } will access the same file. Likewise, if the sequence { chdir (dir_name (NAME)); rename (base_name (NAME), "foo"); } succeeds, you have renamed NAME to "foo" in the same directory NAME was in. */char *
base_name (charconst *name)
{
charconst *base = last_component (name);
size_t length;
/* If there is no last component, then name is a file system root or the empty string. */if (! *base)
return xstrndup (name, base_len (name));
/* Collapse a sequence of trailing slashes into one. */
length = base_len (base);
if (ISSLASH (base[length]))
length++;
/* On systems with drive letters, `a/b:c' must return `./b:c' rather than `b:c' to avoid confusion with a drive letter. On systems with pure POSIX semantics, this is not an issue. */if (FILE_SYSTEM_PREFIX_LEN (base))
{
char *p = xmalloc (length + 3);
p[0] = '.';
p[1] = '/';
memcpy (p + 2, base, length);
p[length + 2] = '\0';
return p;
}
/* Finally, copy the basename. */return xstrndup (base, length);
}
/* Return the length of the basename NAME. Typically NAME is the value returned by base_name or last_component. Act like strlen (NAME), except omit all trailing slashes. */size_t
base_len (charconst *name)
{
size_t len;
size_t prefix_len = FILE_SYSTEM_PREFIX_LEN (name);
for (len = strlen (name); 1 < len && ISSLASH (name[len - 1]); len--)
continue;
if (DOUBLE_SLASH_IS_DISTINCT_ROOT && len == 1
&& ISSLASH (name[0]) && ISSLASH (name[1]) && ! name[2])
return 2;
if (FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE && prefix_len
&& len == prefix_len && ISSLASH (name[prefix_len]))
return prefix_len + 1;
return len;
}